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From Jonathan Shook <jsh...@gmail.com>
Subject Re: writing speed test
Date Tue, 01 Jun 2010 20:00:10 GMT
Also, what are you meaning specifically by 'slow'? Which measurements
are you looking at. What are your baseline constraints for your test
system?


2010/6/1 史英杰 <shiyingjie1983@gmail.com>:
> Hi, It would be better if we know which Consistency Level did you choose,
> and what is the schema of test data?
>
> 在 2010年6月1日 下午4:48,Shuai Yuan <yuanshuai@supertool.net.cn>写道:
>>
>> Hi all,
>>
>> I'm testing writing speed of cassandra with 4 servers. I'm confused by
>> the behavior of cassandra.
>>
>> ---env---
>> load-data app written in c++, using libcassandra (w/ modified batch
>> insert)
>> 20 writing threads in 2 processes running on 2 servers
>>
>> ---optimization---
>> 1.turn log level to INFO
>> 2.JVM has 8G heap
>> 3.32 concurrent read & 128 write in storage-conf.xml, other cache
>> enlarged as well.
>>
>> ---result---
>> 1-monitoring by `date;nodetool -h host ring`
>> I add all load together and measure the writing speed by
>> (load_difference / time_difference), and I get about 15MB/s for the
>> whole cluster.
>>
>> 2-monitoring by `iostat -m 10`
>> I can watch the disk_io from the system level and have about 10MB/s -
>> 65MB/s for a single machine. Very big variance over time.
>>
>> 3-monitoring by `iptraf -g`
>> In this way I watch the communication between servers and get about
>> 10MB/s for a single machine.
>>
>> ---opinion---
>> So, have you checked the writing speed of cassandra? I feel it's quite
>> slow currently.
>>
>> Could anyone confirm this is the normal writing speed of cassandra, or
>> please provide someway of improving it?
>> --
>> Kevin Yuan
>> www.yuan-shuai.info
>>
>>
>
>

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